21 Dec
2015
21 Dec
'15
7:37 p.m.
I have heard that some guys have put a motor in the circuit just to
deal with the harmonics as a filter to shore the sine wave up. An
interesting idea, worth a try, but I bet it works on a case-by-case
basis.
--
Will
On Mon, Dec 21, 2015 at 10:12 PM, Jon Elson <elson at pico-systems.com> wrote:
On 12/21/2015 09:03 PM, William Donzelli wrote:
If you can get a rotary one, those are really nice - just wasteful and
loud. With proper maintenance they last forever, can take a beating,
and do not give waveshape issues that cheap solid state units can
have. And, maybe most importantly, you can make one yourself.
But considering the mix of 50 and 60 Hz stuff you likely have by now
(that is what you get for moving!), spending some decent money on a
real VFD might be worth it. I might think a cheap VFD may give
ferroresonant iron fits with all those extra harmonics.
You can't run electronics with VFDs designed to run motors, only. They put
out PWM chopped square waves at 300+ Volts. A motor's winding inductance
smooths that out to a proper current waveform, and it only causes a little
extra eddy current losses. But, typical transformers will have real fits
with that kind of waveform.
There are "frequency changers" made by Elgar and others that will do the job
right, but they will cost a REAL bundle of cash! (Also known as frequency
converters.)
It may be possible to retune the resonant circuit of the constant voltage
transformer by adding capacitance in parallel to the existing capacitor.
Jon